To paraphrase Keynes: as time (t) => infinity, we're all dead. We don't live our lives in a society at the end of the long run, we live our lives in a society

To paraphrase Keynes: as time (t) => infinity, we're all dead. We don't live our lives in a society at the end of the long run, we live our lives in a society that exists here and now. Social mobility might end up at zero in a thousand years (or ten thousand years, or a hundred thousand years) but here and now we can make real people's lives better.